Shock mounting structures of the prior art which buffer vibration and impact externally applied to a magnetic disk apparatus in which a magnetic disk driving motor is mounted on a base typically have constructions as shown in FIGS. 11, 12, or 13.
FIG. 11 shows a shock mount structure in which a frame 75 is retained by securing a cylindrical shock mount element 72 by a screw 73 protruding from one end thereof to a base 71 on which a magnetic disk and a spindle motor are mounted.
Shock mount 72 has a screw 73 at one axial end that is received in a threaded opening in base 71 and a screw 74 at the other axial end that extends through aperture 76 in frame 75 is secured by a nut 77.
FIG. 12 shows a shock mount structure in which a frame 85 is secured using a shock mounting part 81B with a threaded opening 81A at the bottom of a base 81 on which a magnetic disk driving motor is mounted. The screw 83 protruding from one end of a cylindrical shock mount element 82 is received in the threaded opening 81A of the shock mounting part 81B, to mount the cylindrical shock mount element 82 on the base 81. A bolt 87 extends through a mounting hole 86 in frame 85 and is received in the internally threaded opening 82A of the cylindrical shock mount element 82 to retain the frame.
FIG. 13 shows a shock mount structure in which a frame 95 is secured by forming a cutout 91A at the end of a base 91 on which a magnetic disk driving motor is mounted. Threaded opening 91B is formed in the base extending from the surface of cutout 91A. A bolt 97 is inserted through a through-hole of a bushing-type shock mount element 92 and a mounting hole 96 in frame 95 and received in the threaded opening 91B.
For the shock mounting structure shown in FIG. 11, the manufacturing cost is increased because the nut is used, and a space corresponding to the height of the fastened nut (L) cannot be used for the elastomeric shock mount portion as shown in FIG. 14. Although the space occupied or rendered otherwise unusable by the fastening nut may appear trivial, space within a standard form factor or available within a device becomes a critical consideration in a high density disk storage environment where every effort is made to maximize the storage capacity of the device.
In the shock mounting structure shown in FIG. 12, the diameter of the cylindrical shock mount element 82 cannot provide sufficient shock absorbing capability because the cylindrical member 82 is horizontally arranged. Also, only a small cushion effect can be obtained for the volume of the shock absorbing member 82 because the metal internal thread 82A is mounted in the member 82.
The shock absorbing capability of the structure shown in FIG. 13 is limited because the frame 95 is fixed at the side of the base 91.